Albert Barnes Commentary 2 Kings 7:6

"For the Lord had made the host of the Syrians to hear a noise of chariots, and a noise of horses, even the noise of a great host: and they said one to another, Lo, the king of Israel hath hired against us the kings of the Hittites, and the kings of the Egyptians, to come upon us." — 2 Kings 7:6 (ASV)

It is not important whether the miracle by which God delivered Samaria consisted of a mere auditory illusion (Compare to 2 Kings 6:19–20) or an objective, real sound (compare the marginal references).

The king of Israel has hired... The use of mercenaries was employed by the nations bordering Palestine as early as the time of David (2 Samuel 10:6; 1 Chronicles 19:6–7). Therefore, the Syrians' assumption was far from improbable.

The kings of the Hittites. The Hittites, who are first found in the south (Genesis 23:7) and then in the center of Judea (Joshua 11:3), seem to have retreated northward after the Israelites occupied Palestine. They are found among the Syrian enemies of the Egyptians on monuments from the 19th dynasty (around 1300 B.C.) and appear at that time to have inhabited the valley of the Upper Orontes.

In early Assyrian monuments, they form a great confederacy as the most powerful people of northern Syria, dwelling on both banks of the Euphrates. At the same time, there was a second confederacy of their people further south, which seems to have inhabited the Anti-Lebanon region between Hamath and Damascus. During the time of Benhadad and Hazael, these southern Hittites were a powerful people, especially strong in chariots, and they generally assisted the Syrians against the Assyrians. The Syrians, therefore, seem to have imagined that these southern Hittites had been hired by Jehoram.

The kings of the Egyptians. This is a remarkable expression, since Egypt always appears elsewhere in Scripture as a centralized monarchy under a single ruler. The probability is that the main pharaoh had a prince or princes associated with him on the throne, a practice that was not uncommon in Egypt. The period, which is that of the 22nd dynasty, is an obscure one, and the monuments shed little light on it.